package com.zestinn.smart4j.framework.util;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileFilter;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * @author zestinn
 * @create 2017-09-21 15:46
 */
public final class ClassUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(ClassUtil.class);

    /**
     * 获得类加载器
      */
    public static ClassLoader getClassLoader(){
        return Thread.currentThread().getContextClassLoader();
    }

    /**
     * 加载类
     */
    public static Class<?> loadClass(String className, boolean isInitialized){
        Class<?> cls = null;
        try {
            cls = Class.forName(className, isInitialized, getClassLoader());
        } catch (ClassNotFoundException e){
            LOGGER.error("load class failure", e);
        }
        return cls;
    }

    /**
     * 默认参数的加载类
     */
    public static Class<?> loadClass(String className){
        return loadClass(className, false);
    }

    /**
     * 获取指定包下的所有类
     */
    public static Set<Class<?>> getClassSet(String packageName){
        Set<Class<?>> classSet = new HashSet<Class<?>>();
        try {
            Enumeration<URL> urls = getClassLoader().getResources(packageName.replace(".", "/"));
            while (urls.hasMoreElements()){
                URL url = urls.nextElement();
                if (url != null){
                    String protocol = url.getProtocol();
                    if (protocol.equals("file")){
                        String packagePath = url.getPath().replaceAll("%20", "");
                        addClass(classSet, packagePath, packageName);
                    } else if (protocol.equals("jar")){
                        JarURLConnection jarURLConnection = (JarURLConnection)url.openConnection();
                        if (jarURLConnection != null){
                            JarFile jarFile = jarURLConnection.getJarFile();
                            if (jarFile != null){
                                Enumeration<JarEntry> jarEntries = jarFile.entries();
                                while (jarEntries.hasMoreElements()){
                                    JarEntry jarEntry = jarEntries.nextElement();
                                    String jarEntityName = jarEntry.getName();
                                    if (jarEntityName.endsWith(".class")){
                                        String className = jarEntityName
                                                .substring(0, jarEntityName
                                                        .lastIndexOf(".")).replaceAll("/", ".");
                                        doAddClass(classSet, className);
                                    }
                                }
                            }
                        }
                    }
                }
            }

        }catch (Exception e){
            LOGGER.error("get class set failure", e);
            throw new RuntimeException(e);
        }
        return classSet;
    }


    private static void addClass(Set<Class<?>> classSet, String packagePath, final String packageName){
        File[] files = new File(packagePath).listFiles(
                new FileFilter() {
                    public boolean accept(File pathname) {
                        return (pathname.isFile() && pathname.getName().endsWith(".class")) ||
                                pathname.isDirectory();
                    }
                }
        );
        for (File file :files){
            String fileName = file.getName();
            if (file.isFile()){
                String className = fileName.substring(0, fileName.lastIndexOf("."));
                if (StringUtils.isNotEmpty(packageName)){
                    className = packageName + "." + className;
                }
                doAddClass(classSet, className);
            } else {
                String subPackagePath = fileName;
                if (StringUtils.isNotEmpty(packagePath)){
                    //tofix
                    if (packagePath.endsWith("/")){
                        packagePath = packagePath.substring(0, packagePath.length()-1);
                    }
                    subPackagePath = packagePath + "/" + subPackagePath;
                }
                String subPackageName = fileName;
                if (StringUtils.isNotEmpty(packageName)){
                    subPackageName = packageName + "." + subPackageName;
                }
                addClass(classSet, subPackagePath, subPackageName);
            }
        }

    }

    private static void doAddClass(Set<Class<?>> classSet, String className){
        Class<?> cls = loadClass(className, false);
        classSet.add(cls);
    }

}
